Testing lake-level reconstructions based on rock magnetic proxies for the sediment record of Laguna Cháltel (Patagonia, Argentina). Issue 1 (May 2020)

• Record Type: Journal Article
• Authors: Irurzun, María A.; Palermo, Pedro; Gogorza, Claudia S. G.; Sinito, Ana M.; Aldana, Milagrosa; Costanzo-Álvarez, Vincenzo; Ohlendorf, Christian; Zolitschka, Bernd
• Is Part Of: Quaternary research. Volume 95:Issue 1(2020)
• Page Start: 113
• Page End: 128
• Publication Date: 2020-05
• Subjects: Rock magnetism, -- Palaeoclimate, -- Lake sediments, -- Lake level, -- Wind intensity, -- Late Holocene; Geology, Stratigraphic -- Quaternary -- Periodicals; Glacial epoch -- Periodicals; Stratigraphie -- Quaternaire -- Périodiques; Époque glaciaire -- Périodiques; Geology, Stratigraphic; Glacial epoch; Quaternary Geologic Period; Electronic journals; Periodicals; 551.79
• DOI: 10.1017/qua.2020.15
• Languages: English
• ISSNs: 0033-5894

Abstract

Abstract: This study was carried out on sediment cores collected with a gravity corer from Laguna Cháltel, an almost circular crater lake located in Patagonia, Argentina (49.9°S, 71°W). The main magnetic carrier was Ti-magnetite in the pseudo–single domain range. A model using magnetic grain size and concentration, previously applied to Laguna Potrok Aike to infer lake-level changes, was used for Laguna Cháltel. The main requirement to apply the model is uniform magnetic mineralogy, which is the case for Laguna Cháltel. After magnetic data were compared with previously studied lake levels, it was found that the magnetic proxies that best follow hydrologic changes are ARM/SIRM (anhysteretic remanent magnetisation/saturation of isothermal remanent magnetisation) and ARM. The concentration proxy (ARM measured with a 100 mT alternating field and 0.05 mT direct field) was also used as wind indicator. High wind strength was found at around 3650 cal yr BP, and low wind strength for the last century. ARM/SIRM and ARM were used to infer the strength of fluvial runoff into the lake for a core collected close to the shore and near a tributary. The results show that the magnetic model is promising for inferring lake-level variations, particularly in Patagonian lakes.